An axle of a railroad vehicle, a trailer or the like is supported by a vehicle frame via a plurality of axle bearings (e.g., a pair of axle bearings). Various types of loads, such as a radial load or an axial load, are applied to an axle bearing during traveling of a vehicle.
Japanese Patent Provisional Publication No. JP2008-82720A describes a bearing testing machine in which an axle for testing (hereafter, referred to as a “testing machine shaft”) is attached to an axle bearing being a testing target, and the testing machine shaft is rotated while applying a radial load and an axial moment load to the axle bearing so that performance of the axle bearing used in an actual vehicle can be simulatively evaluated.